1. Field of the Invention
Embodiments of the present invention generally relate to prevention of abnormal breathing sounds (e.g., snoring), adverse consequences, illness or death in persons due to partial or complete blockage of the upper airway.
2. Description of the Related Art
A common and potentially serious disorder in humans involves involuntary closure of the airway during sleep. This disorder is known as “sleep-disordered breathing” or “obstructive sleep apnea” (OSA). In persons with OSA, there is involuntary closure or reduction in caliber of a portion of the airway that connects the atmosphere to the lungs. The upper portion of the airway (the “upper airway”) consists of two passageways, the nasal airway and the oral airway. These two passageways merge to become a single passageway. Portions of the upper airway just behind the tongue are known as the soft palate, the pharynx, the hypopharynx, etc.
In persons affected by OSA, closure, reduction in patency or increased airflow resistance of the upper airway occurs during sleep, due to a combination of physiological changes associated with sleep (including relaxation of muscles) and the anatomy of the upper airway (which is generally smaller or more crowded than in normal individuals). In persons prone to sleep apnea, a portion or portions of the muscular walls of the upper airway may become narrow or collapse, leading to reduction in airflow (“hypopnea”), cessation of airflow (“apnea”), increase in airflow turbulence or increased resistance to airflow within the airway. In the instance of collapse, the upper airway is blocked, breathing stops, air movement to the lungs ceases, and the oxygen level in the blood tends to decrease. As a response to this process (or to less severe manifestations, such as hypopneas or increased airway resistance), a brief arousal usually occurs in the brain. As a consequence of the brief arousal, the muscle tone in the walls of the upper airway returns to waking levels, and the airway abnormality is corrected—i.e. airway resistance and patency return to normal levels.
Generally, following each event, the patient returns to sleep, until another partial or complete upper airway collapse occurs and the process repeats itself. Depending on the severity in an individual case, the number of events may range from a few per hour of sleep to more than 100 events per hour of sleep. This process disrupts normal sleep. As a consequence, patients typically suffer from the effects of sleep deprivation. Such effects may include daytime drowsiness, tiredness or fatigue, difficulties with mental concentration or memory, mood changes, reductions in performance or increases in mistakes, and increased risk of accidents. Additionally, OSA is known to increase the risk of development of other medical problems
Snoring is a mild form of sleep-disordered breathing in which increased airflow turbulence occurs. The snoring sounds result from tissue vibration within the nasal or oral airway. While snoring has been traditionally regarded as a social or cosmetic problem, recent studies suggest that snoring may be linked to the development of health problems, including high blood pressure.
Airway closure during sleep generally occurs at one or both of two levels in the upper airway: the soft palate and the hypopharynx (base of the tongue). At either level, the anterior tissue can collapse against the posterior pharyngeal wall, which makes up the rear wall of the throat. Additionally, the side (lateral) walls of the upper airway can collapse inward partially, or completely against each other. The lateral walls of the airway are susceptible to collapse in many patients with obstructive sleep apnea and other forms of sleep-related breathing disorders. In these cases, prevention of collapse of the airway only in the anterior-posterior dimension is insufficient to maintain normal airway patency. Even after extensive airway surgery for sleep apnea (which primarily addresses the anterior-posterior dimension of the airway), the patient may continue to have problems with breathing during sleep, due to lateral wall collapse or dysfunction.
Several types of treatment are available for obstructive sleep apnea and other sleep-related breathing disorders. The most common treatment consists of an air pressure delivery system that applies greater than atmospheric pressure to all walls of the upper airway to reduce the potential for full or partial collapse. Many people have difficulty using this device or prefer not to use it for various reasons. Also, surgical reconstruction of the airway or dental devices may be used. These treatments, however, often fail to treat the problem adequately.
Accordingly, a need exists in the art for an improved method and system for treating sleep apnea and other sleep-related breathing disorders.